#!/usr/bin/python3
# -*- coding:utf-8 -*-
"""
"""


class RunnableMixIn(object):
    def run(self):
        print('Running...')


class FlyableMixIn(object):
    def fly(self):
        print('Flying...')


class Animal(object):
    pass


# 大类:
class Mammal(Animal):
    pass


class Bird(Animal):
    pass


# 各种动物:
class Dog(Mammal, RunnableMixIn):
    pass


class Bat(Mammal, FlyableMixIn):
    pass


class Parrot(Bird, FlyableMixIn):
    pass


class Ostrich(Bird, FlyableMixIn, RunnableMixIn):
    pass


def main():
    dog = Dog()
    dog.run()
    os = Ostrich()
    os.run()
    os.fly()


if __name__ == "__main__":
    main()
